Rotary dental apparatus.



M. WENTWORTH & W. J. GARBUTT. ROTARY DENTAL APPARATUS.

APPLICATION FILED MAY 11, 1908.

937, 126, Patented Oct. 19, 1909.

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UNITED STATES PATENT OFFICE.

MONTA WENTWORTH AND WILLIAM J. GARBUTT, 0F MILWAUKEE, WISCONSIN.

ROTARY DENTAL APPARATUS.

' Specification of Letters Patent.

Patented Oct. 19, 1909.

Application filed May 11, 1908. Serial 'No. 432,282.

To all whom it may concern:

Be it known that W6,MONTA WENTWORTH and WILLIAM J. GARBUflT, residing in Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented new and useful Improvements in Rotary Dental Apparatuses, of which the following is a description, reference being had to the accompanymg drawings, which are a part of this specification.

Our invention has relation to improvements in rotary dental apparatuses, more especially intended for use as arotary tooth brush.

It is the primary object of the invention to provide a simple and improved form of rotary dental appliance, preferably in the form of a rotary tooth brush adapted for cleaning teeth and bridges which an ordinary tooth brush is incapable of properly cleaning and thereby rendering the device particularly adapted for home use.

With the above primary object, and other incidental objects, in' view, the invention consists of the devices and parts, or their equivalents, as hereinafter set fort In the accompanying drawing, Figure 1 is a vertical sectional view through the casing of the device, also showing a portion of the flexible shaft broken away and a portion of the crank broken away; and Fig. 2 is a vertical sectional view of the complete apparatus taken on a plane at right angles to Fig. 1.

Referring to the drawing, the numeral 3 indicates an outer casing which may be of any desirable form best adapted for containing the interior mechanism.

In the specific embodiment of the inven tion illustrated in the drawing, we have shown a spring motor as the particular means for rotating the flexible brush or other tool of the apparatus. The spring 4 of this motor consists of a flat coiled spring having the inner end thereof secured, by means of a pin or rivet 5, to 'an enlarged central portion or drum 6 the ends whereof form shoulders for a" purpose hereinafter described of a transverse shaft 7 said shaft having its ends mounted in and extending through the sides of the casing. One of the extended ends of the shaft carries a crank 8, said crank preferably having a threaded engagement with the end of the shaft, with the threads so arranged as to cause a tightening of the crank when said crank is turned in a direction to wind the spring upon the drum. Rigidly mounted on the shaft adjacent to one shoulder formed by the end ofthe drum is a ratchet wheel 9, with which wheel a pawl 10 pivoted to the side of the casing is adapted to engage. The pawl is so arranged as to slip by the teeth of the ratchet wheel when winding up the spring, but is adapted to engage the teeth to prevent reverse rotation of the shaft, after the winding operation is completed. A large toothed wheel 11 has its hub 12 mounted loosely on the shaft 7 The left hand end of this hub (Fig. 1) abuts against the right hand shoulder formed by the drum 6. The right hand end of the hub is formed or provided with a friction disk 13 which bears against the inner face of the adjacent side of the casing. The right hand extended end of shaft 7 is threaded to receive thereon a nut 14. Interposed between this nut and a boss outstanding from the side of the casing is a tongued washer 15, the tongue thereof fitting a longitudinal groove 16 in the shaft.

The large toothed wheel 11 meshes with a pinion 17 rigid on an intermediate shaft 18, said shaft having its hearings in the sides of the casing. Also rigidly mounted on shaft 17 is a toothed wheel 19 of greater circumferential area than the wheel 11. This toothed wheel 19 mesheswith a pinion 20 on an upper shaft 21, said shaft having its ends rotatably mounted in the sides of the casing. One end of shaft 21 extends through one of the sides of the casing, and has coupled thereto the inner end of a flexible shaft, said shaft being of an ordinary form of construction, that is to say, composed of an inner closely coiled spring 22 and an outer flexible cover 23. The lower end of the spring joins a shank 24 which passes freely through a tubular handle portion 25. To the end of this shank is clutched the tooth brush 26, or other dental tool. The outer end of the spring 4 is coiled around and connected to a pin 27 extending laterally from the inner side of the toothed wheel 11.

In the operation of the invention, the crank 8 is turned until the spring 4 is tightly wound upon the drum. When the spring is wound to the desired extent the pawl 10, through its engagement with the ratchet wheel 9, prevents reverse rotation of the shaft 7. Upon the completion of the winding operation the spring 4 of course, starts to uncoil, and by reason of the connection of the outer end of said spring with the pm 27 extending laterally from the wheel 11, rotation is imparted to said wheel, and thls rotation, through the train of gearing consisting of the pinion 17 toothed wheel 19 and pinion 27, is imparted to the shaft 21, and finally to the flexible shaft 23. By grasping the tubular handle 25, the tooth brush 26, or other dental tool, may be applied to the teeth, and by reason of the very rapid rotation imparted to the brush an effective cleaning of the teeth is secured, and the user is enabled to reach and properly clean teeth and bridges which would be inaccessible with'an ordinary form of tooth brush.

It will be noticed that the arrangement of the gears is such that the comparatively slow rate of speed of rotation to the wheel 11 is multiplied, so that the shaft 21 and the flexible shaft 23 with its tooth brush are caused to rotate at a very rapid rate of speed.

In order to regulate or graduate the rate of speed of rotation of the flexible shaft, the nut 14 is turned so as to bring the friction disk 13 into more or less frictional engagement with the side of the casing. For instance, if it is desired that the speed of rotation should be decreased, the nut is turned in a direction to bring the friction disk firmly against the side of the casing so as to increase the frictional engagement, or, if it is desired to stop entirely the uncoiling of the spring, the nut may be turned to such an extent as to create such frictional engagement between the disk 13 at the side of the casing as to prevent entirely the rotation of the toothed wheel 11, as against the influence exerted to rotate said wheel by the tendency of the spring to uncoil. Again, if it is desired that a rapid rotation of the flexible shaft be secured, the nut is turned in a direction to loosen the frictional engagement of the disk with the side of the casing. It is obvious that when the nut is turned in a direction to bring the disk into firm frictional engagement with the side of the casing, the direction of turning of the nut must be such as to act on the threads of the shaft 7 so as to draw said shaft toward the right of Fig. 1, so as to cause the shoulder at the right hand end of the drum 6 to act against the end of the hub 12 of the toothed wheel 11, in order to force the said hub and its wheel, and consequently the disk, toward the right. With a reverse turning of the nut, the shoulder formed by the right hand end of the drum is brought out of engagement with the end of the hub, and consequently the frictional contact between the disk and the side of the casing is relieved.

It is obvious that if the inner side of the nut 14 were placed directly against the side of the casing there would be considerable friction between the two surfaces, sufficient perhaps to hold the nut stationary whenever there is a turning of the shaft 7, whereby the extent of frictional engagement between the disk 12 and the side of the casing will be changed each time the crank is turned. It is to avoid this danger that we employ a washer 15 disposed between the inner side of the nut and the side of the casing, said washer provided with a tongue extending into the longitudinal groove 16 of the shaft, By this provision, whenever the shaft '7 is turned by the manipulation of the crank or handle 8, the washer is necessarily turned with said shaft, and also the nut. In consequence there is no tendency of the shaft to turn in the nut.

WVhile we have herein shown and described a spring motor arrangement, yet we do not wish to be understood as specifically limiting ourselves thereto, inasmuch as any desirable form of motor, as, for instance, a hand power motor, an electircally operated motor,

or a compressed air operated motor might be employed without departing from the spirit and scope of our invention.

lVe prefer to provide at the top of the casing a receptacle 28 which is ada )ted to hold the flexible shaft when said sha 't is not in use. The said shaft can be thrown back into the receptacle without detaching the same, or if preferred, the said flexible shaft may be unscrewed from shaft 21, and be placed in the receptacle in its detached condition.

What we claim as our invention is:

1. In a rotary dental apparatus, the combination of a casing, a motor driven shaft having its ends mounted in the sides of the casing, and having one end extending through one side of the casing and provided with threads, a toothed wheel having its hub looesly mounted on the shaft, and having one end bearing against a shoulder of the shaft, and its opposite end provided with a friction plate adapted to bear against one side of the casing, a nut turned on to the threads of the extended end of the motor driven shaft, a flexible shaft carrying a dental tool, a shaft mounted in the sides of the casing and to which the flexible shaft is connected, a train of gearing between the motor driven shaft and the shaft to which the flexible shaft is connected, the gears being so proportioned as to cause an increased speed of rotation of the shaft to which the flexible shaft is connected, and means for preventing reverse rotation of the motor driven shaft.

2. In a dental apparatus, the combination of a casing, a motor driven shaft having its ends mounted in the sides of the casing, and having one end extending through one side of the casin and provided with threads and with a longltudinal groove, a toothed wheel having its hub loosely mounted on the shaft, and having one end bearing against a shoulder of the shaft, and its opposite end provided witha friction plate adapted to bear against one side of the casing, a nut turned on to the threads of the extended end of the motor driven shaft, a washer disposed on the motor driven shaft between the nut and the side of the casing, the said washer provided with a tongue extending into the groove of the shaft, a flexible shaft carrying a dental tool, a shaft mounted in the sides of the-casing and to which the flexible shaft is connected, a train of gearing between the motor driven shaft and the shaft to which the flexible shaft is connected, the gears being so proportioned as to cause an increased speed of rotation of the shaft to which the flexible shaft is connected, and means for preventing reverse rotation of the motor driven shaft.

In testimony whereof, we affix our signatures, in presence of two witnesses.

MONTA WENTWORTH. W. J. GARBUTT.

Witnesses:

ANDREW J. WAYNE, LEW. CLOUD. 

